The following description relates to a management method and management system for storage areas, and more particularly to a management method for storage areas applicable in storage devices, accessed by use of the Internet SCSI (iSCSI) Protocol, to name servers and directories when the configuration of storage areas has been altered and to a management system for executing it.
Storage Area Network (SAN) environments in which host computers and storage devices, such as disk arrays, are connected by a network are in growing use. More recently, interest is focused on the Internet SCSI (iSCSI) which uses an IP network as the SAN and communicates data by mounting the SCSI Protocol on the Transmission Control Protocol (TCP). The iSCSI has the advantage of allowing low-cost architecture of a SAN by making use of existing IP switches and ether cables. An entity for performing iSCSI Protocol communication has “storage nodes” and “portals”. A storage node has a unique identifier “iSCSI name” and becomes the sender and receiver of communication. A portal has a network address and provides means of communication. A storage node sends and receives data by mutual communication via a portal.
Details of the iSCSI are described in the following reference, Julian Satran et al., Internet Draft, draft-ietf-ips-iscsi-20.txt, pp. 20-48.
An IP network makes possible communication with geographically distant sites, and the number of devices that can be connected within a single network is far greater than what a fiber channel or the like can accommodate. For this reason, if information regarding storage areas accessible by host computers (for instance disk volumes created on a disk array as logical areas) are individually set for each host computer, their management will entail complex work. In view of this problem, there is proposed a method by which disk volumes can be discovered without having to set information on disk volumes for each host computer by placing many nodes that communicate by the iSCSI Protocol under centralized management in a database and having each host computer to acquire information it needs from the database.
Regarding this method, for instance the reference, Josh Tseng et al., Internet Draft, draft-ietf-ips-isns-22.txt, pp. 7-13 describes the Internet Storage Name Service (iSNS) in which information on devices capable to be communicated by the iSCSI Protocol is centrally managed. Thus, by having the addresses and port numbers of portals used by a given storage node for communication registered in the iSNS, other storage nodes are enabled to discover that node and to acquire from the iSNS the address they need for communication. Further by dividing each storage node to be managed into groups called discovery domains, the nodes which a given storage node can discover can be limited to nodes registered in the same domain.
Further, the following reference, Mark Bakke et al., Internet Draft, draft-ietf-ips-iscsi-slp-07.txt, pp. 4-14, describes a method by which iSCSI nodes are discovered by use of a Service Location Protocol (SLP) which manages information on the services provided within the network. Thus, by registering one storage node and the address and port number of one portal which the node uses for communication in the SLP Directory Agent as the URL of the service, discovery from other nodes is made possible. Further, by designating the node which is permitted to communicate as an attribute of a service to be registered, each node can discover only those nodes it can communicate with.